Re: IXP

[Mike Leber <mleber () he net>]

Leo Bicknell wrote:
> In a message written on Fri, Apr 24, 2009 at 01:48:28AM +0000, Paul Vixie wrote:
> > i think i saw several folks, not just stephen, say virtual wire was how
> > they'd do an IXP today if they had to start from scratch.  i know that
> > for many here, starting from scratch isn't a reachable worldview, and so
> > i've tagged most of the defenses of shared subnets with that caveat.  the
> > question i was answering was from someone starting from scratch, and when
> > starting an IXP from scratch, a shared subnet would be just crazy talk.
>
> I disagree.
>
> Having no shared subnet renders an exchange switching platform
> useless to me.  If I have to go to all the work of configuring both
> ends in a exchange point operator provisioning system (and undoubtly
> being billed for it), assigning a /30, and configuring an interface
> on my router then I will follow that procedure and order a hunk of
> fiber.  Less points of failure, don't have to deal with how the
> exchange operator runs their switch, and I get the bonus of no
> shared port issues.
>
> The value of an exchange switch is the shared vlan.  I could see
> an argument that switching is no longer necessary; but I can see
> no rational argument to both go through all the hassles of per-peer
> setup and get all the drawbacks of a shared switch.  Even exchanges
> that took the small step of IPv4 and IPv6 on separate VLAN's have
> diminished value to me, it makes no sense.
>
> It's the technological equvilient of bringing everyone into a
> conference room and then having them use their cell phones to call
> each other and talk across the table.  Why are you all in the same
> room if you don't want a shared medium?

I second that.

We got to go through all the badness that was the ATM NAPs (AADS, 
PacBell NAP, MAE-WEST ATM).

I think exactly for the reason Leo mentions they failed.  That is, it 
didn't even require people to figure out all the technical reasons they 
were bad (many), they were fundamentally doomed due to increasing the 
difficulty of peering which translated to an economic scaling problem.

i.e. if you make it hard for people to peer then you end up with less 
peers and shared vlan exchanges based on things like ethernet outcompete 
you.

Been there done that.

We've already experienced the result of secure ID cards and the 
PeerMaker tool.  It was like pulling teeth to get sessions setup, and 
most peers plus the exchange operator didn't believe in oversubscription 
(can you say CBR?  I knew you could), so you end up with 2 year old 
bandwidth allocations cast in stone because it was such a pain to get 
the peer to set it up in the first place, and to increase bandwidth to 
you means your peer has to reduce the bandwidth they allocated to 
somebody else.

Mike.

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